PuTTY

PuTTY is a terminal client for connecting to another machine over SSH, Telnet, Rlogin or a raw socket, and for talking to devices over a serial port. It opens a terminal window and nothing else — there is no file manager, no tabs, no built-in editor.

Connection details are kept as named sessions, so a host, port, username, key file and terminal preferences can be saved once and reopened later. Keys are handled by the companion tools that come with it: PuTTYgen generates and converts key pairs, Pageant holds decrypted keys in memory so a passphrase is typed once per session, and pscp and psftp move files over the same connection.

It started on Windows and is still most associated with it, though the source builds on Unix as well. Serial console access makes it a common choice for configuring routers and embedded boards.